Department of Chemistry and Nanoscience & Technology Institute, Wonkwang University, 460 Iksandaero, Jeonbuk 54538, Republic of Korea.
Dyntem Corporation, 460 Iksandaero, Iksan, Jeonbuk 54538, Republic of Korea.
J Chromatogr A. 2020 Aug 16;1625:461267. doi: 10.1016/j.chroma.2020.461267. Epub 2020 May 31.
We describe the design and performance evaluation of a portable gas chromatograph suitable for the analysis of volatile organic and odorous compounds at trace levels. The system comprises a carbon nanotube sponge preconcentrator, an electronic pressure control (EPC) unit, a temperature-programmable column module, and a fast-response photoionization detector. A built-in tablet computer controls instrumental parameters and chromatogram display functions. The compact GC with dimensions of 35 cm (l) × 26 cm (w) × 15 cm (h) is self-contained, weighing less than 5 kg without a battery pack, and uses no auxiliary compressed gases. Our design has three main advantages over conventional portable GCs: recharging configuration of ambient air as the carrier gas using a miniature diaphragm pump, precise control of column flow by the built-in canister and EPC system, and rapid thermal desorption of the preconcentrator facilitated by intrinsic resistivity of the carbon nanotube sponge. A 30 m, 0.28 mm I.D. capillary column operated at a head pressure of 14 psi provided a peak capacity of 55 for a 10 min isothermal analysis. The temperature-programmability feature could decrease the analysis time of less than 5 min for vapor mixture of benzene, toluene, ethylbenzene, and o-xylene. More than a 100-fold increase in sensitivity by preconcentrating a sample adsorption volume of 90 mL resulted in improved detection limits of 0.13 (benzene), 0.20 (toluene), 0.23 (ethylbenzene), and 0.28 (o-xylene) ppb (v/v). Our instrument displayed good stability and reproducibility of retention times (< 0.14% RSD) and intensities (< 4.5% RSD) for continuous measurements using the preconcentrator over 10 h. Thus, continuous and on-site determinations of trace volatile organic compounds in air samples with this instrument appear feasible.
我们描述了一种适用于痕量挥发性有机化合物和气味化合物分析的便携式气相色谱仪的设计和性能评估。该系统包括碳纳米管海绵预浓缩器、电子压力控制（EPC）单元、程序升温柱模块和快速响应光离子化检测器。内置平板电脑控制仪器参数和色谱图显示功能。这款紧凑型 GC 的尺寸为 35 cm（长）×26 cm（宽）×15 cm（高），自成一体，不含电池组时重量小于 5 公斤，且无需使用辅助压缩气体。与传统的便携式 GC 相比，我们的设计有三个主要优点：使用微型隔膜泵将环境空气作为载气进行再充电配置、内置罐和 EPC 系统对柱流进行精确控制、以及碳纳米管海绵的固有电阻促进预浓缩器的快速热解吸。在 14 psi 的柱头压力下运行的 30 m、0.28 mm I.D. 毛细管柱实现了 55 的峰容量，用于 10 min 等温分析。程序升温功能可将苯、甲苯、乙苯和邻二甲苯蒸气混合物的分析时间缩短至 5 分钟以下。通过预浓缩 90 mL 的样品吸附体积，灵敏度提高了 100 多倍，检测限改善至 0.13（苯）、0.20（甲苯）、0.23（乙苯）和 0.28（邻二甲苯）ppb（v/v）。我们的仪器在使用预浓缩器 10 小时以上的情况下，显示出保留时间（<0.14% RSD）和强度（<4.5% RSD）的良好稳定性和重现性。因此，使用该仪器对空气中痕量挥发性有机化合物进行连续和现场测定似乎是可行的。
